Wooden post with protective coating and method for making same

ABSTRACT

A protected wooden post having a coating of a hardened protective material that surrounds the peripheral surface of the post to protect the wood thereunder from marring and abrasion, typically from the use of a nylon string trimmer to trim grass and weeds from around the base of the embedded post. A hardenable protective coating can be applied to a wooden post, either before the wooden post is installed into the ground, or after the wooden post is embedded into the ground. Typical wooden posts include mailbox posts, swing set posts, fence posts and telephone poles. The hardened protective coating typically includes a UV protector to diminish the effect of UV light from sunlight on the integrity of the protective coating material.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claism the benefit of copending U.S. Provisional PatentApplication No. 60/579,010, filed Jun. 12, 2004.

BACKGROUND

The United States government has operated a postal service since 1775when the Continental Congress named Benjamin Franklin the firstPostmaster General. Rural free delivery service to individual residencesin the rural America first began in 1896, and by 1908, much of Americareceived its main daily by postal delivery.

Presently, a significant proportion of the population receives the U.S.mail in residential mail boxes positioned on or near the resident'sproperty and along the side of the road. There are a variety of mailboxes in use, but the majority of them are shoebox-sized or largercontainers that are affixed to the top end of an upright support, suchas a wooden post. The bottom end of the support is buried into theground to secure the mailbox from swaying and falling over.

Many residents position the mailbox in the lawn along side the road. Inthe course of cutting the grass, the resident or a lawn careprofessional will use a trimming device to trim grass growing close tothe base of the mailbox post that can not cut with a lawn mower. Atypical grass trimming device has an electric or gasoline-operated motorthat drives a spool hub at an opposite end via an elongated shaft. Thehub carries a length of flexible trimming string, a portion of whichprojecting outwardly from hub 20. As the motor is operated, the hubrotates at great speed. The outwardly-projecting section of line isswung in a circle about the axis of the shaft, whereby it will contactand cut off grass or other material in its path. Examples of suchdevices are shown in U.S. Pat. Nos. 2,708,335; 3,006,421; 3,608,291;4,200,978; and 4,584,771.

The flexible plastic string used in the grass trimmers is designed andselected for durability. The string typically is made of a flexibleplastic with a high hardness that resists wear and breaking whenstriking the earth, asphalt, concrete, stones and other hard or sharparticles. Some grass trimming strings are designed with star-shapedprofiles that provide the outer surface with edges that improve thecutting function.

The strength, durability and design of the flexible plastic string alsocauses damage and wear along the base of wooden mailbox posts whentrimming grass close to the base. After repeated grass cutting andtrimmings, the periphery of the base of the wooden post can experiencesignificant wear. As many mailbox wooden posts are made ofpressure-treated wood, the wearing away of the outer wood surface alongthe base exposes the wood in toward the interior which tends to haveless of the water-resistant chemicals. With time, the wood along theworn base of the wooden post begins to deteriorate rapidly withadditional wear and water. In certain northern regions, snow that ispropelled from a roadway by a snowplow can impact and snap off themailbox post at its base.

At the same time, lawn mowers housings often strike and gouge the baseof the wooden post in the operator's effort to cut the grass as close aspossible to the post.

Therefore, a need exists for a means for preventing the wear of the baseof wooden posts by grass trimmers and lawn mowers.

SUMMARY OF THE INVENTION

The invention is a protected wooden post for positioning within theground to an intended depth, comprising a wooden post having a firstembedded end, a second upper end, and a ground-level positionintermediate the first and second ends, and a hardened protectivecoating covering the peripheral surface of the wooden post and extendingfrom proximate the ground-level position toward the second end. Thewooden post can include a post made from pressure-treated wood.

The invention also relates to a method of protecting the base of awooden post from wear and abrasion, prior to or after positioning intothe ground, comprising the steps of: applying a hardenable protectivematerial to cover the peripheral surface along the length of the post,extending from proximate a ground-level position intermediate the firstand second ends of the post, toward the second end; and hardening theprotective material into a protective coating.

The wooden post can include, but is not limited to, a mailbox post, afence post, a swing or play set post, a deck support post, and atelephone pole.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a wooden post, used as a mailbox post, having a protectivecoating that covers a portion of the post intermediate the ends.

FIG. 2 shows a wooden post positioned within the ground and having aprotective coating covering the periphery of the post proximate theground level.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows an improved wooden post 60 of the present invention,typically a four-sided post of square or rectangular cross section,having a length defined by an upper end 64 and an embedded end 62intended to be embedded into the ground to support the upper end 64 ofthe post 60 in an upright or tilted position. Such a post is typicallyused for the mounting of a mailbox 100, as shown in FIG. 1, and forother uses including fence posts and wooden play frames and swing sets.Intermediate the embedded end 62 and upper end 64 of the post is aground-level position 70, where the distance from the ground-levelposition 70 to the embedded end 62 approximates the depth that the postwould be embedded into the ground in an intended use for the woodenpost. The wooden post 60 comprises a protective coating 10 thattypically covers the outer peripheral surface of the wooden post 60. Theprotective coating typically extends from proximate the ground-levelposition 70, toward the upper end 64. The protective coating can alsoextend from proximate the ground-level position 70 toward the embeddedend 62. Preferably, the coating 10 extends from below the ground-levelposition 70 (that is, toward the embedded end 62) toward the upper end64. Typically, the protective coating covers a length of the post offrom about 5 cm to about 50 cm, more typically from about 10 cm to about30 cm, and extends from a position 72 about 5 cm to about 20 cm (ormore) above the ground-level position 70 (that is, toward the upper end64), toward the first end 62 to a position 74 about 2 cm to 15 cm, ormore, below the ground-level position 70. In other embodiments, theprotective coating can extend from above the ground-level position 70,to the very first end of the embedded end 62.

The protective coating is typically formed from a hardenable or curableliquid protective material that is applied as a liquid coating onto thesurface of the wooden post to adhere directly thereto. The liquidcoating hardens or cures into the hardened, protective coating. Thehardenable liquid material can harden or be hardened by a variety ofmeans, including solvent evaporation, melt cooling, and chemicalreaction. A protective coating typically hardens or cures, afterapplication of the liquid coating, into a dense, solid, and adherentcoating.

The protective coating typically comprises a binder that provides itshardness, uniformity and coherence. The binder ability to form a dense,tight film is directly related to its molecular size and complexity.Binders that have the highest molecular weight can form films by theevaporation of the vehicle, while binders with smaller molecular weightwill generally be chemically reacted in situ. Non-limiting examples ofthe binders can be selected from the group consisting of:oxygen-reactive binders, including alkyds, epoxy esters, urethanealkyds, and silicone alkyds; lacquers, including polyvinyl chloridepolymers, chlorinated rubbers, acrylics, and bituminous materials (e.g.,tar); heat conversion binders, including hot melt materials, organisolsand plastisols; co-reactive binders, including epoxies andpolyurethanes; condensation binders; coalescent binders including latexand poly-fluoroethylene/vinyl ether (FEVE); and inorganic binders,including post-cured silicates, self-curing water silicates, andself-curing solvent-based silicates.

The protective material can be transparent, translucent, or opaque, andcan have a natural or other color.

An optional component of the protective coating is an opacifying agent.One type of opacifying agent is a pigment. A pigment is essentially adry powder that is insoluble in the binder and solvent medium, and thatconsequently needs to be mixed in by a dispersion technique. Other typesof opacifying agents can include titanium dioxide, talc and silicapowders. The opacifying agent can be naturally occurring or a man-madeorganic compound. The opacifying agent can contribute severalproperties, including color, film reinforcement, sag control, increasedcoverage, gloss control, and adhesion.

Another optional component of the protective coating is a UV absorber orblocking compound, which can diminish the effect of UV light fromsunlight on the integrity of the protective coating material. UVabsorbers suitable for use in the protective coating are well known andused widely in industrial coatings. Non-limiting examples of UVabsorbers include benzophenone and benzotriazole.

The protective coating typically comprises one or multiple solvents. Thechoice of solvents influences viscosity, flow properties, drying speed,spraying or brushing characteristics, and gloss. There is no universalsolvent for protective coatings, the best solvent in one system beingoften impractical for another. Asphalts, for example, can be readilydissolved by hydrocarbons but are insoluble in alcohols. One of the mostserious problems associated with coatings is the wrong choice of solventsince it can severely affect the curing and adhesion characteristics ofthe final coating. Typical solvents include: aliphatic hydrocarbons orparaffins such as naphta or mineral spirits are typically used withasphalt, oil and vinyl based coatings; aromatic hydrocarbons, such astoluene, xylene or some of the higher boiling homologs, which aretypically used with chlorinated rubbers, coal tars and certain alkyds;ketones such as acetone, methyl ethyl ketone, methyl iso-butyl or amylketone and many others, which are used with vinyls, some epoxies andother resin formulations; esters such as ethyl, n-propyl, n-butyl oramyl acetates, which are used commonly as latent solvents (a type ofsolvent that just swells the binder at room temperature) with epoxy andpolyurethane formulations; alcohols such as methyl, propyl, iso-propylor butyl alcohols and cyclo-hexanol, which are good solvents for highlypolar binders such as phenolics; ethers and alcohol ethers, such asethyl ether, which are excellent solvents for some of the naturalresins, oils, and fats; and water, which with recent regulations toreduce the emission of volatile organic compounds (VOCs) produced byorganic solvents, has been forcing the coating industry to reconsiderthe applicability of water as a solvent.

The improved wooden post is used to protect the base of the embeddedpost from wear from both natural causes and from mechanical abrasion.For example, mechanical abrasion can be caused by the use of mechanicalstring trimmers that use a nylon string to cut grass and weeds aroundthe base of the embedded post. Typically, the protective material usedto form the protective coating is selected to have a hardness that isgreater than the hardness of the plastic used for the trimming string.Typical protective materials include curable epoxy compositions asdescribed in U.S. Pat. Nos. 4,383,090, 4,177,173, 3,978,151, 6,573,309,6,084,039, 4,170,613, 4,172,157, 4,377,457, and 4,424,252, allincorporated herein by reference. Use of the layer of protectivematerials proximate to the based of the embedded post serves to preventwear of the outer wood surface along the base, which in time could causethe worn base to deteriorate and weaken.

A method of manufacturing a protected wooden post, such as the one shownin FIG. 1, comprises the steps of: providing a wooden post having afirst embedded end, a second upper end, and a ground-level positionintermediate the first and second ends; applying a liquid coating of ahardenable protective material to the peripheral surface of the post,extending from proximate the ground-level position and toward the upperend; and hardening the liquid coating into the hardened protectivecoating. The liquid protective material can be sprayed on, brushed on,or roller-applied onto the post. The applied liquid protective coatingis then hardened, or allowed to harden, into the hardened protectivecoating. The hardened protective coating is not tacky or soft, and istypically sufficiently hard and durable to resists mechanical wear. Thestep of hardening can include allowing the material to harden with timedue to solvent evaporation, chemical reaction, and temperature change.Typically, the hardenable protective material is applied at a thicknessof from about 0.5 mm to about 3 mm. The material can be uniformly ornon-uniformly applied, or intermittently applied to the outer peripheryof the post.

The invention also includes a method of applying, as described above,the liquid coating of the hardenable protective material to the base ofthe wooden post, such as the post 60 shown in FIG. 2, while embedded orpositioned within the ground 80, and allowing the hardening of theliquid coating into the hardened protective coating 10. Typically thehardenable protective coating 10 has been applied from a position 72above the ground-level position 70, down to proximate the ground-levelposition 70 of the post 60. It is not necessary that the coating beapplied completely to the level of the ground; by “proximate” meansabove the ground-level position, to the ground-level position, or belowthe ground-level position. The method and the protected post of theinvention can prevent marring and damage of the underlying wood of thepost near the base when grass 66 or other vegetation is trimmed using astring trimmer.

EXAMPLES Example 1

A 7-foot long, 6-inch by 6-inch pressure-treated wooden post isprovided, and a fresh mixture of an epoxy resin and polymercaptan aminesis applied around the peripheral surface of the wooden post to athickness of about 1 mm, and along a 25 cm length, starting at adistance of from about 30 cm from a first embedded end of the post,toward the second upper end. The protective material begins to hardenabout five minutes after the mixture is formed, and is typically fullycured and hardened after 10 minutes more. The protected wooden post canthen be inserted into the ground, wherein about 10 cm of the hardenedprotective layer extends about ground level. When a string trimmerdevice is used to trim grass from around the mailbox post, the peripheryof protective material resists scarring or tear by the nylon trimmerstring, and protects the wooden post thereunder from the same.

Example 2

An existing vertical mailbox post was provided, which had been embeddedinto the ground in a grass lawn. The mailbox post was a pressure-treatedwooden post, having a height of about 5 feet and a 6-inch by 6-inchcross section. The base of the mailbox post near the ground wassubstantially free of damage to its outside peripheral surface. A freshmixture of an epoxy resin and polymercaptan amines was formed andapplied with a 2-cm wide plastic bristle brush, around the periphery ofthe wooden post to a thickness of about 1 mm, from near the ground levelto a height of about 15 cm. The epoxy mixture began to harden about fiveminutes after the mixture was formed, and fully cured into a protectivematerial after 15 minutes. When a string trimmer device was used thenext day to trim grass from around the mailbox post, the periphery ofprotective material resisted scarring or tear by the nylon trimmerstring, and protected the wooden post from the same. Repeated use of thenylon string trimmer to trim grass from around the base of the mailboxpost resulted in no loss in the integrity of the epoxy protectivecoating, and protected the surface of the wooden mailbox post fromscratches, scarring, and tears in the wood.

Example 3

The wooden legs of an A-frame swing set are coated with a hardenablemixture of epoxy resin and polymercaptan amine, along the lower lengthof the legs, and the mixture is allowed to harden. The legs are coatedso that once the legs are installed into the ground, the hardenedcoating extends above the ground level for 15-20 centimeters. Grass andweeds that grow around the swing set legs can be trimmed with a nylonstring trimmer, which cuts the grass and weeds, but strikes only thehardened coating, thereby not damaging the underlying wooden leg.

Example 4

Similar procedures and results are obtained as in Examples 1 and 2 witha telephone pole, fence posts, and deck support posts.

1. A protected wooden post for positioning within the ground to anintended depth, comprising a wooden post having a first embedded end, asecond upper end, and a ground-level position intermediate the first andsecond ends, and a hardened protective coating covering the peripheralsurface of the wooden post and extending from proximate the ground-levelposition and extending toward the second end.
 2. The protected woodenpost according to claim 1 wherein the wooden post is selected form thegroup consisting of a mailbox post, a fence post, a swing or play setpost, a deck support post, and a telephone pole.
 3. The protected woodenpost according to claim 1 wherein the protective coating comprises abinder that is selected from the group consisting of: oxygen-reactivebinders, including alkyds, epoxy esters, urethane alkyds, and siliconealkyds; lacquers, including polyvinyl chloride polymers, chlorinatedrubbers, acrylics, and bituminous materials; heat conversion binders,including hot melt materials, organisols and plastisols; co-reactivebinders, including epoxies and polyurethanes; condensation binders;coalescent binders; and inorganic binders, including post-curedsilicates, self-curing water silicates, and self-curing solvent-basedsilicates.
 4. The protective wooden post according to claim 1 whereinthe protective coating extends from below the ground-level position, toabove the ground-level position and toward the upper end.
 5. Theprotected wooden post according to claim 1 wherein the protectivecoating covers a length of the post of from about 5 cm to about 50 cm,and extends from a position about 5 cm to about 20 cm above theground-level position, to a position about 2 cm to 15 cm below theground-level position.
 6. A method of protecting the base of a woodenpost from wear and abrasion, comprising the steps of: applying ahardenable protective material to cover the peripheral surface along thelength of the post, extending from proximate a ground-level positionintermediate the first and second ends of the post, toward the secondend; and hardening the protective material into a protective coating. 7.The method according to claim 6 wherein the hardenable protectivematerial is applied to the wooden post prior to positioning the woodenpost into the ground.
 8. The method according to claim 6 wherein thehardenable protective material is applied to the wooden post whilepositioned in the ground.
 9. The method according to claim 6 wherein thewooden post is selected form the group consisting of a mailbox post, afence post, a swing or play set post, a deck support post, and atelephone pole.
 10. The method according to claim 6 wherein theprotective coating comprises a binder that is selected from the groupconsisting of: oxygen-reactive binders, including alkyds, epoxy esters,urethane alkyds, and silicone alkyds; lacquers, including polyvinylchloride polymers, chlorinated rubbers, acrylics, and bituminousmaterials; heat conversion binders, including hot melt materials,organisols and plastisols; co-reactive binders, including epoxies andpolyurethanes; condensation binders; coalescent binders; and inorganicbinders, including post-cured silicates, self-curing water silicates,and self-curing solvent-based silicates.
 11. The method according toclaim 6 wherein the hardenable protective material is applied from belowthe ground-level position, to above the ground-level position and towardthe upper end.
 12. The method according to claim 6 wherein thehardenable protective material is applied to cover a length of the postof from about 5 cm to about 50 cm, and to extend from a position about 5cm to about 20 cm above the ground-level position, to a position about 2cm to 15 cm below the ground-level position.